1. Field of the Invention
The present invention is directed to wire for thermal spraying; to spraying systems for applying material coatings to a substrate; and in certain aspects to wire and coating made with it that inhibit marine growth and corrosion.
2. Description of Related Art
xe2x80x9cThermal sprayingxe2x80x9d refers to a variety of processes for depositing both metallic and non-metallic materials on a substrate to form a coating. Metals, cermets, ceramics, plastics and mixtures thereof in the form of powders, rods or wires may be used as coating material. Heat for melting the material is supplied by electric arc, plasma arc, or combustible fuel gases and compressed air or process gases form an accelerated stream of molten coating material. The material builds up on the substrate and cools to form the coating.
Electric arc spray processes use electrically charged wire which is fed by a wire feeder to an arc spray gun in which the wires converge, arc, and melt in a high temperature zone (e.g. 15,000 degrees F. or higher) created by the arc. A compressed air stream is directed to the arc zone and atomizes the molten material produced from the melting wire. The stream flows from the gun for coating onto a desired substrate.
Molten particle velocities average 100 meters per second; deposit thicknesses average 0.001 to 0.003 inches per pass; and deposition rates range between 10 to 40 pounds of material per hour depending on the material and the amperage. By compassing the arc in a gun head relatively little heat is transferred by the molten material tot he substrate. Sprayable materials include, but are not limited to, carbon steels, stainless steels, oxides, carbides, nickel alloys, copper, copper alloys, bronze, aluminum, aluminum alloys, zinc, babbitt, and molybdenum. Such materials may be spray to produce a coating or to rebuild a part.
The present invention, in certain aspects, discloses a wire for thermal spraying that includes: 1. copper and/or copper alloy and 2. aluminum and/or aluminum alloy and/or zinc and/or zinc alloy . In one aspect such a wire has an outer sheath of pure aluminum (e.g. 1100 type aluminum) or of aluminum alloy. The outer sheath may, e.g., be made of materials as in Table I. In certain aspects the aluminum alloy contains at least 95% aluminum by weight. The wire, in certain aspects, has a core of pure copper or of copper alloy including, but not limited to copper alloyed with tin, zinc, nickel, manganese, iron and/or silicon. In certain aspects the copper alloy contains at least 80% copper by weight. The core may be made, e.g., of the materials in Table II.
The sheath, in certain aspects, has a thickness ranging between 0.010 inches and 0.020 inches for a wire, e.g., of {fraction (1/16m)} inches in diameter. The sheath for a wire of about {fraction (3/16)} inches in diameter ranges between 0.010 inches and 0.150 inches thick. By weight the total material of the core, in certain embodiments, ranges between 1% and 60% of the wire""s total weight. By weight the sheath, in certain embodiments, ranges between 40% and 99% of the total wire weight. The core may include both copper and copper alloy with copper present in a range of 1% to 60% by weight and copper alloy present in a range of 1% to 60% by weight of the total core weight. The sheath may include both aluminum and/or zinc and aluminum alloy and/or zinc alloy in a range of 40% to 99% by weight of the total sheath weight.
The core may be in powder form or it may itself be a solid wire. In certain embodiments the sheath as described above is made of zinc, zinc alloy, aluminum or aluminum alloy. In other aspects the sheath is made of a combination of any two or more of these materials. The sheath may be made, e.g. of any of the materials in Table III or of a combination of any two or more of them.
In certain embodiments, the wire is made by enclosing the core in the sheath. This can be done by any of the well-known cored wire making processes. Typical sheathed wire or core wire forming processes are disclosed in U.S. Pat. Nos. 3,777,361; 3,648,356; 3,631,586; 3,600,790; 3,436,248; 4,013,211; and the prior art cited in these patentsxe2x80x94all of which are incorporated fully here for all purposes.
In other embodiments a wire according to the present invention is made by melting and combining the core material and sheath material to produce a solid combination of the two, in one aspect in the form of rods, and then extruding a wire of suitable diameter from the rods.
In other embodiments, a wire (or strand, filament) or wires of core material is twisted together with a wire or wires of sheath material to form a multi-component wire which has no outer sheath. Alternatively, such a multi-component wire may have an outer sheath of sheath material.
What follows are some of, but not all, the objects of this invention. In addition to the specific objects stated below for at least certain preferred embodiments of the invention, other objects and purposes will be readily apparent to one of skill in this art who has the benefit of this invention""s teachings and disclosures. It is, therefore, an object of at least certain preferred embodiments of the present invention to provide:
New, useful, unique, efficient, nonobvious wires and methods for thermal spraying;
Such wires which have a core of core material and a sheath of sheath material as disclosed herein;
Such wires made of one or more wires of core material and one or more wires of sheath material, with or without a sheath of sheath material; and
Such wires used in thermal spraying systems to inhibit marine growth and corrosion.
Certain embodiments of this invention are not limited to any particular individual feature disclosed here, but include combinations of them distinguished from the prior art in their structures and functions. Features of the invention have been broadly described so that the detailed descriptions that follow may be better understood, and in order that the contributions of this invention to the arts may be better appreciated. There are, of course, additional aspects of the invention described below and which may be included in the subject matter of the claims to this invention. Those skilled in the art who have the benefit of this invention, its teachings, and suggestions will appreciate that the conceptions of this disclosure may be used as a creative basis for designing other structures, methods and systems for carrying out and practicing the present invention. The claims of this invention are to be read to include any legally equivalent devices or methods which do not depart from the spirit and scope of the present invention.
The present invention recognizes and addresses the previously-mentioned problems and long-felt needs and provides a solution to those problems and a satisfactory meeting of those needs in its various possible embodiments and equivalents thereof. To one skilled in this art who has the benefits of this invention""s realizations, teachings, disclosures, and suggestions, other purposes and advantages will be appreciated from the following description of preferred embodiments, given for the purpose of disclosure, when taken in conjunction with the accompanying drawings. The detail in these descriptions is not intended to thwart this patent""s object to claim this invention no matter how others may later disguise it by variations in form or additions of further improvements.